Cushioning device for underframes



Sept. 29, 1964 J. B. CUNNINGHAM 3,150,780 f CUSHIONING DEVICE F 0RUNDERFRAMES Filed June 25, 1962 2 Sheets-Sheet 1 5. fm n ma N N W m t W-N .NN ma A Q al w IIIIII II Illhh. lll lll rr- Illll l "nl {Iii} Il.,mwu..." l ||l M nu 1 1111111 111 I f HWNIHHM mw .||.|Ir|. n 1. ilflli....TI... fn? 4 .IIII v cercata EL@ l" N RMN. RN- k.. MN \\QN N\ N n N N.N .NSN n, J Q l 1 IL dauw .tif HHH l L Ad. u.. l M .KI MII m a Sept.29, 1964 J. B. CUNNINGHAM cusHIoNING DEVICE FOR UNDERFRAMES 2Sheets-Sheet 2 Filed June 25, 1962 mmf United States Patent O 3,156,780CUSHINING DEVCE FR UNDERFRAMES lames B. Cunningham, 6927 Forest vHillDrive, Si. Louis 20, Mo. Filed .fune 25, 1962, Ser. N0. 204,784 iaclaims. (ci. zia-s2) This invention relates to a combined spring andfriction snubbing device for railway cars with floating draft sills.

An object of the invention is to provide a snubbing device in which theenergy absorption is effected by means of spring and wedge actuatedfriction shoes and a single pair of springs act in parallel to resistmovement of the lloating sill away from neutral position and to restoreit to neutral position whereby both the resistive and restorative forceis equal to the sum of both spring loads.

It is an additional object of the invention to provide such a device inwhich movements of the sill in either direction away from or towardneutral position are snubbed by the friction shoes.

It is a further object to provide a friction centering device in whichthe element which transmits energy from the springs .to the frictionshoes is constantly in tension and hence never in compression when thesill is in olfcenter positions.

An additional object is to provide a relatively simple, inexpensive, andeasily maintained device of this character.

The foregoing and additional objects and advantages will be apparentfrom the following description of the u accompanying drawings, in which:

FIG. 1 is a horizontal sectional view, taken on line 1-1 of FIG. 2 ofthe central portion of the center sill of a railway freight carunderframe embodying the invention.

FIG. 2 is a longitudinal vertical sectional view along line 2-2 of FIG.1.

FIG. 3 is a transverse vertical sectional view along line 3-3 of FIG. 1.

FIG. 4 is a transverse vertical sectional view along line 4-4 of FIG. 1.

FIG. 5 is a transverse vertical sectional view along line 5--5 of FIG.l.

FIG. 6 is a horizontal section along line 1-1 of FIG. 2 showing thefloating sill in an olf-center position after being struck on its lefthand end.

Throughout the following specification and claims, the terms innenouter, inward, outward, inwardly, outwardly and the like shall be usedto denote relative proximity to the longitudinal center of theunderframe.

Referring now to the drawings, FIG. l shows the center sill portion of acar underframe, which comprises an outer iixed center sill 1 extendingthe full length of the car and forming the usual backbone of the carunderframe. Sill 1 is built up of outwardly open channels 3 and a topcover plate 5 secured by welding to the upper ilanges of the channels.An inner floating sill 9, of the usual AAR hat-section, formed bywelding two Zs together along the adjacent edges of their upper flanges,is slidably received within sill 1. The ends of lloating sill 9 may beformed in the usual way as draft gear pockets to mount conventionaldraft gear and couplers.

At the center of the car, within and axially aligned lengthwise offloating sill 9, is positioned a casting comprising a short tube 11 andan integral base plate 13, which is secured to the bottom flanges offixed sill channels 3. Tube 11 is formed with outwardly facing fiat pads12 at its opposite sides, slidably engageable with the inner uprightsurfaces of sliding sill 9, for guiding the latter in its longitudinalmovement. Within tube 11, intermediate its ends, is positioned anexpansible shoe device comprising sectoral friction shoes 19 of quadrantform having convex outer segmental cylindrical surfaces 20 fric-Patented Sept. 29, 1964 ice tionally engageable with the inner surface1S of tube 11, and central concave cylindrical surfaces 20a withoutwardly flared ends 2012, which cooperate -to form a central aperturethrough the shoe device. A rod 15, formed intermediate its ends withspaced apart opposing conical Wedges 17, passes through the centralaperture formed by concave cylindrical surfaces 20a and is normallypositioned therein with the wedges 17 slightly spaced from the ilaredend surfaces of :the aperture so that when rod 15 moves axially, it willcause expansion of the shoe device into frictional engagement with theinner surface of tube 11 and will also cause the shoe structure to movelengthwise of the tube. For transmitting movement from the draft sill tofriction shoes 19, at each end of the friction shoes an outwardly opencup-shaped inner spring seat 23 is received within the ends of tube 11.To permit slight initial movements of the sill from neutral positioneach spring seat 23 has, on its inner end which is spaced a shortdistance outwardly from the flat outer face of adjacent wedge 17, anannular flange 26 normally seated against the ends of the friction shoes19 coil springs 25, the opposite ends of which are seated against outerseats 27, also mounted on rod 15. The outer rims of inner seats 23 areformed with outwardly extending flanges 24, which are normally spaced aslightly greater distance outwardly from the ends of tube 11 than arethe inner ends of spring seats 23 from wedges 17, and are adapted forengagement with the rim of tube 11 upon slight movement of the floatingsill from its centered position. Seats 27 are normally positionedequidistantly from the center of the car by abutments 29 which aresecured to center sill 1, and normally abut adjacent ends of spacertubes 3l which are mounted on rod 15 and are welded at their outer endsto collars 33. The latter are adjustably positioned on the threaded ends35 of rod 15 by a nut 37. For transmitting movements of iloating sill 9to spring seats 27 and to rod 15, through collar 33, iloating sill 9rigidly mounts lug bars 39 on its inner walls, with their inner endsnormally engaging outer spring seats 27 and their outer ends spaced thesame distance inwardly from collar 33 as inner spring cap outer anges 24are from the rim of tube 11.

With this arrangement it will be evident that initial movement of thefloating sill will be transmitted directly to struck end outer springseat 27 by struck end lugs 39, and through struck end spring 2S, struckend inner spring seat 23 and its inner ilange 24, whereby shoes 19 aremoved in the same direction, but without expansion, into frictionalengagement with tube 11, compressing opposite end spring 25 againstopposite end outer spring seat 27, which is held immobile by oppositeend abutments 29. When the predetermined initial movement is exceededstruck end inner spring seat 23 is held against further inward movementby engagement of its outer llange 24 with tube 11, and opposite end lugs39 engage opposi-te end collar 33, pulling rod 15 toward the oppositeend. This causes struck end wedges 17 to engage shoes 19, therebyexpanding them into engagement with the internal surface of tube 11 andmoving them lengthwise of the tube, thus snubbing Ithe movement of thefloating sill. At the same time struck end lugs 39, acting throughstruck end outer spring seat 2'7, are further compressing struck endspring against the immobilized struck end inner spring seat 23 andmoving shoes 19 which are moving opposite end inner spring seat 23 tocompress opposite end spring 25 against opposite end outer spring seat27, which is immobilized by engagement with opposite end fixed abutments29. Thus springs 25, though axially aligned with each other, act inparallel to oppose movement of the floating sill from its normal neutralor centered position.

Operation of the device is as follows: When an impact is received, forexample, by the left hand end of sill 9, left hand lugs 39 on the insideof sill 9 urge left hand also,

spring outer seat 27 to the right, compressing left hand spring 25against left hand inner spring seat 23 and causing the latter to movetoward the right, its inner annular liange 26 engaging shoes i9, andthrough the latter, right hand inner spring seat Z3, compressing righthand spring ZS against right hand outer spring seat 27, which isprevented from moving to the right by abutment 29. When outer flange 24of left hand inner spring seat 23 engages the adjacent end of tube il,further movement of fioating sill 9 toward the right will cause righthand lugs 39 to engage right hand collar 33, which, acting through righthand nut 3'7, will urge rod l5 to the right, thus pulling the wedges 17to the right and thereby expanding friction shoes 19 into frictionalengagement with the inner surface of tube il, such frictional engagementeffectively snubbing movements of the sill in the right hand direction.This movement of friction shoes 19 to the right also compresses righthand spring 25 against right hand outer spring seat 27. Movement of rodl to the right also causes left hand coilar 33, acting through left handspacer 3i and left hand outer spring seat 27, to compress left handspring against its immobilized inner seat 23. Floating sill Si continuesmoving to the right until all excess kinetic energy is dissipated or theend stops (not shown) on the left hand end of the floating sill strikesthe striker casting (not shown) on the ends of fixed sill l. When thisoccurs, left hand spring 25 will expand, and being restrained againstfurther movement to the right by the engagement of inner spring seatflanges 24 with the left hand end of tube 1l, will urge left hand outerspring seat 27 toward the left. Acting through left hand spacer 3i, lefthand collar 33 will be similarly urged to the left, and acting againstleft hand nut 37, will place operating rod l5 in tension, tending tomove wedges f7' and with them shoes l@ toward the left, to centeredposition. Similarly right hand spring 2S will expand against itsimmobilized ou'ter seat 27, urging its inner seat 23 against the flatouter face of right hand wedge E7 and thus urging rod l5 to the left.Movement of rod l5 to the left, acting through right hand collar 33 andright hand lugs 39, causes corresponding movement of draft siii 9leftward toward centered position, complete return to centered positionbeing effected by the expansion of left hand spring 2S against left handouter spring seat 27 and the engagement of the latter with left handlugs 39, whereby left hand lugs 39 are returned to their normalposition, with their right hand ends aligned with left hand abutmentsZ9. When the sill has returned to centered, or neutral position, anyremaining kinetic energy tending to produce ovcrtravcl is immediatelyresisted by reverse action of the parts.

The absorption of the impact force is accomplished by the cushioningeffect of the springs and the snubbing effeet of the friction betweenthe shoes and the tube. This friction force is produced by the action ofthe spring on the friction shoe wedges, which forces the shoes againstthe inner surface of the tube. This friction force also reacts on thefriction sh e wedges in the same manner as the spring force, therebycreating additional friction for snubbing. Because of this combinationof forces which produces cushioning and snubbing, the great-e' theimpact force, the greater the cushioning and snubbing forces are, untilthe full travel of the sill reached. The sill travel is iimitcd by theengagement of strikers at the ends of the car, which occurs just priorto the springs going solid, thus protecting the device against extremeloads.

The details of the levice be varied substantially without departing fromthe spirit of invention, and the exclusive use of those Iications comewithin tbn scope of the appended claims is contemplate What is claimedis:

. In combination with underframing and a draft member longitudinallymovable relative thereto, an element fixed. to said underframing andhaving a surface extending lengthwise thereof, a shoe device normallypositioned intermediate the ends of said fixed element and adapted forsliding frictional engagement with said surface, said shoe device beingformed with oppositely tapered end surfaces, an elongated member havinga pair of tapered surfaces engageable with the tapered end surfaces ofsaid shoe device for moving said shoe device lengthwise of said fixedelement and into frictional engagement with said surface extendinglengthwise thereof, rst spring seats normally abutting the ends of saidshoe device and adapted alternately to seat against the ends of saidfixed element and to abuttingly engage portions of said elongated memberupon predetermined movement of said draft member, second spring seatsspaced outwardly from said first seats and held against outward movementonly relative to said underframing, springs extending between and seatedon adjacent first and second seats, means on said draft member normallyin engagement with said second spring seats and adapted to urge the sametoward said first seats and adapted also to urge the adjacent ends ofsaid elongated member outwardly when said predeermined movement of saiddraft member is exceeded, and means carried by said elongated member andnormally engaging said second spring seats for transmitting the opposingspring forces to said elongated member whereby to center the latterlengthwise of the car.

2. Structure according to claim l in which said fixed element is an openended tubular member and the transverse dimension of said shoe device issmaller than that of said tubular member, said shoe device beingcxpansible into frictional engagement with the inner surface of saidtubular member.

3. Structure according to claim 2 in which said shoe structure is formedwith a central aperture and said oppositely tapered end surfaces of saidshoe structure are flared ends of the central aperture, said elongatedmember passing through said central aperture, said tapered surfaces ofsaid elongated member being similar in contour to said flared ends andnormally being in spaced mating relation thereto.

4. ln combination with car underframing and a draft memberlongitudinally movable relative thereto, an openended tubular memberfixed to said underframing and extending lengthwise thereof, anexpansible shoe device normally positioned intermediate the ends of saidmember and adapted for sliding frictional engagement with the innersurface of said tubular member when expanded, said expansible shoestructure being formed with a central aperture with outwardly flaredends, an elongated member extending lengthwise of said sills and passingthrough the aperture in said expansible shoe device and having a pair oftapered surfaces received within the flared ends of said shoe deviceaperture and engageable therewith for expanding said shoe device, firstspring seats surrounding said elongated member outwardly of its taperedsurfaces and having their inner ends normally in engagement with theopposite ends of said shoe device and their outer ends normally spacedfrom but engageable with the opposite ends of said tubular member,springs seated in said first seats and extending lengthwise of saidelongated member, second spring seats surrounding said elongated memberand abutting the outer ends of said springs, abutments fixed to saidunderframng and engaging said second seats for preventing outwardmovements of said second seats lengthwise of said first sill, collars onsaid clongated member outwardly of said second seats, means maintainingsaid second seats a predetermined minimum distance inwardly from saidcollars, and stop elements on said draft member normally in engagementwith outer surfaces of said second spring seats and normally spaced frombut engageable with inner surfaces of said collars.

5. Structure according to claim 4 in which said underframing comprises ahollow center sill and said draft member is received therein.

6. Structure according to claim 5 in which said draft member is a hollowsill and said tubular member, said elongated member, said springV seats,spring abutments,

and collars are positioned therein, said stop elements being mounted oninternal surfaces of said draft sill.

7. Structure according'to claim 6 in which the bottoms of said sill andsaid draft member are open, said tubular member being formed with ahorizontal laterally extending base secured underlying said sill andsaid draft member and secured at its ends to said center sill andslidably supporting said draft sill.

8. Structure according to claim 7 in which said abutments are carried bya horizontal base plate underlying both said sills and secured at itsends to said center sill.

9. Structure according toV claim 4 in which the bore of said tubularmember is cylindrical and said shoe device comprises a plurality ofsectoral shoes the outer surfaces of which are convex cylindricalsegments and the inner surfaces of which are opposinf7 concave conicalsegments connected by smaller diameter concave cylindrical segments,said tapered surfaces of said elongated member being opposing conicalsurfaces.

10. A device for cushioning relative movements of two structureslengthwise of the evice, comprising longitudinally extending surfacemeans fixed to one of the structures, a shoe normally positionedintermediate the ends of said surface means and adapted for slidingfrictional engagement with said surface means, said shoe being formedwith oppositely tapered end surfaces, an elongated member having a pairof tapered'surfaces engageable with the tapered end surfaces of saidshoe for moving said shoe lengthwise of and into frictional engagementwith said surface means, springs extending in both directionslongitudinally of the device from said shoe and both held at their innerends against movement longitudinally inwardly from the normal positionthereof relative to said one structure and to said elongated member andat their outer ends against outward movement relative to both saidstructures, said elongated means being held against substantial movementrelative to said other structure whereby relative movements of saidstructures away from their normal positions will move said shoe intofrictional engagement with and longitudinally of said surface means andwill compress both said springs separately.

References Cited in the le of this patent UNITED STATES PATENTS 773,387Gallagher Oct. 25, 1904 1,998,388 Scharfenberg Apr. 16, 1935 2,425,364Dath Aug. 12, 1947 2,752,048 Fillion lune 26, i956 FOREIGN PATENTS672,562 France Sept. 17, 1928 772,194 France Apr. 21, 1934 321,677 ItalyOct. 12, 1934

1. IN COMBINATION WITH CAR UNDERFRAMING AND A DRAFT MEMBERLONGITUDINALLY MOVABLE RELATIVE THERETO, AN ELEMENT FIXED TO SAIDUNDERFRAMING AND HAVING A SURFACE EXTENDING LENGTHWISE THEREOF, A SHOEDEVICE NORMALLY POSITIONED INTERMEDIATE THE ENDS OF SAID FIXED ELEMENTAND ADAPTED FOR SLIDING FRICTIONAL ENGAGEMENT WITH SAID SURFACE, SAIDSHOE DEVICE BEING FORMED WITH OPPOSITELY TAPERED END SURFACES, ANELONGATED MEMBER HAVING A PAIR OF TAPERED SURFACES ENGAGEABLE WITH THETAPERED END SURFACES OF SAID SHOE DEVICE FOR MOVING SAID SHOE DEVICELENGTHWISE OF SAID FIXED ELEMENT AND INTO FRICTIONAL ENGAGEMENT WITHSAID SURFACE EXTENDING LENGTHWISE THEREOF, FIRST SPRING SEATS NORMALLYABUTTING THE ENDS OF SAID SHOE DEVICE AND ADAPTED ALTERNATELY TO SEATAGAINST THE ENDS OF SAID FIXED ELEMENT AND TO ABUTTINGLY ENGAGE PORTIONSOF SAID ELONGATED MEMBER UPON PREDETERMINED MOVEMENT OF SAID DRAFTMEMBER, SECOND SPRING SEATS SPACED OUTWARDLY FROM SAID FIRST SEATS ANDHELD AGAINST OUTWARD MOVEMENT ONLY RELATIVE TO SAID UNDERFRAMING,SPRINGS EXTENDING BETWEEN AND SEATED ON ADJACENT FIRST AND SECOND SEATS,MEANS ON SAID DRAFT MEMBER NORMALLY IN ENGAGEMENT WITH SAID SECONDSPRING SEATS AND ADAPTED TO URGE THE SAME TOWARD SAID FIRST SEATS ANDADAPTED ALSO TO URGE THE ADJACENT ENDS OF SAID ELONGATED MEMBEROUTWARDLY WHEN SAID PREDETERMINED MOVEMENT OF SAID DRAFT MEMBER ISEXCEEDED, AND MEANS CARRIED BY SAID ELONGATED MEMBER AND NORMALLYENGAGING SAID SECOND SPRING SEATS FOR TRANSMITTING THE OPPOSING SPRINGFORCES TO SAID ELONGATED MEMBER WHEREBY TO CENTER THE LATTER LENGTHWISEOF THE CAR.